This invention relates in general to articulated rotor systems for helicopters of the type which utilize elastomeric blade retention bearings and deals more particularly with improved blade retention means for such rotor assemblies.
A conventional rotor system of the aforedescribed general type usually includes a rotor hub which defines a plurality of generally radially outwardly opening blade attachment chambers. Each chamber contains an elastomeric blade retention bearing which retains an associated rotor blade in assembly with the rotor hub and further supports it for articulated motion relative to the hub. A typical rotor system of the aforedescribed type is illustrated and described in U.S. Pat. No. 3,759,631 to Rybicki, issued Sept. 18, 1973. Typically, the outer face of the blade retention bearing is bolted to the hub and formed the outer end wall of the blade attachment chamber in which it is contained. Such arrangement is generally satisfactory for use with a rotor system of the type which includes a metal hub structure, however, it is not suitable for use with a nonmetallic rotor hub, as, for example, a hub made from composite material which includes layers of woven fabric or fibrous material held together by a suitable binder such as epoxy resin. The present invention is concerned with the provision of improved blade retention means for rotor hubs of the latter type.